Regimen for providing smooth tooth feel

ABSTRACT

The present invention provides a method of treating a tooth surface to provide smooth tooth feel benefits, comprising the steps: (a) contacting the tooth surface with a first composition comprising a water-insoluble calcium phosphate; and thereafter (b) contacting the tooth surface with a second composition comprising an organophosphate.

FIELD OF THE INVENTION

The present invention relates to a method of treating tooth surface witha first composition and then a second composition to provide a smoothtooth feel.

BACKGROUND OF THE INVENTION

Oral care products, such as toothpastes and mouth rinses, are routinelyused by consumers as part of their oral care hygiene regimen. Oral careproducts are often formulated to provide both therapeutic and cosmetichygiene benefits. Therapeutic benefits include dental caries prevention,gingivitis prevention, and hypersensitivity control. Cosmetic benefitsinclude control of plaque and calculus formation, removal and preventionof tooth stain, tooth whitening, breath freshening, and overallimprovements in mouth feel impression which can be broadly characterizedas mouth feel aesthetics. Smooth tooth surface or slick tooth feel isgenerally considered as an important sign of thorough cleaning andeffective delivery of these benefits.

Abrasives, such as silica and calcium carbonate, are widely used intoothpastes to remove dental stains and polish the teeth, thereforesmoothing the tooth surface and providing a slick tooth feel. However,the abrasion of abrasives on the tooth surface may lead to abrasivedamages on dental enamel. Such abrasive damages include enamel loss(e.g., scratches, micro-cracks, etc.) and enamel thinning, which mayroughen the tooth surface and make it easier for undesirable bacteria todeposit and invade into the tooth and consequently result in enameldestruction. On the other hand, a pellicle film to which the dentalstains affix usually forms on the surface of the dental enamel withinminutes after teeth are cleaned by selective binding of glycoproteinsfrom saliva. The slick tooth feel may diminish soon after the adhesionof the thin coating to the dental enamel.

Therefore, there is a need to solve this problem. There is a need tosmooth the tooth surface without abrasive damage to dental enamel. Thereis also a need to restore the tooth surface smoothness even after enamelloss or thinning. Finally, there is a need to provide a long-lastingsmoothing effect on the tooth surface.

SUMMARY OF THE INVENTION

The present invention attempts to solve one or more of these problems.In one aspect, the present invention provides a method of treating atooth surface, comprising the steps:

(a) contacting the tooth surface with a first composition comprising awater-insoluble calcium phosphate, wherein the water-insoluble calciumphosphate has a calcium to phosphorus molar ratio from 1:1 to 10:1; andthereafter

(b) contacting the tooth surface with a second composition, wherein thesecond composition comprises an organophosphate having the formula:

wherein R is a hydrocarbyl comprising 4 to 22 carbon atoms; X and Y areeach independently an alkylene comprising 2 to 4 carbon atoms; a and bare each independently an integer selected from 0 to 20, wherein a+b isin the range from 0 to 20; Z¹ and Z² are each independently selectedfrom hydrogen, hydrocarbyl comprising 1 to 26 carbons preferablycomprising one or more ether moieties, and a counter ion, provided thatat least one of Z¹ and Z² is hydrogen or a counter ion.

In another aspect, the present invention provides an oral care kit,comprising:

(a) a first product containing a first composition, wherein the firstcomposition comprises 0.01% to 99% by weight of a water-insolublecalcium phosphate having a calcium to phosphorus molar ratio from 1:1 to10:1;

(b) a second product containing a second composition, wherein the secondproduct is a mouth rinse with a pH from 6 to 8 and a viscosity from 100cps to 5000 cps, and wherein the second composition comprises 0.01% to99% by weight of an organophosphate as defined above; and

(c) instructions instructing a user to first use the first product tocontact a tooth surface and thereafter immediately use the secondproduct to contact the tooth surface.

In a further aspect, the present invention provides an oral care productcomprising a first container and a second container, wherein the firstcontainer contains a first composition comprising 0.01% to 99% by weightof a water-insoluble calcium phosphate which has a calcium to phosphorusmolar ratio from 1:1 to 10:1, and the second container contains a secondcomposition comprising 0.01% to 99% by weight of an organophosphate asdefined above; and wherein the product optionally contains instructionsinstructing a user to dispense the first composition before the secondcomposition is dispensed.

One aspect of the invention generally provides a sequential applicationsystem of a calcium source followed by a specific organophosphate ontothe tooth surface. Without wishing to be bound by theory, the first stepof applying the calcium source is believed to seal micro-cracks orcrevices in the tooth structure, and the second step of applying thespecific organophosphate is believed to seal the calcium into the toothstructure. By this sequential application system, perceptible andmeaningful improvements are delivered to the tooth surface, bypotentially providing new crystal growth at sites of enamel loss orthinning, restoring tooth surface smoothness and/or building up auniform protection layer to prolong the tooth surface smoothness.

These and other features, aspects, and advantages of the presentinvention will become evident to those skilled in the art from thedetailed description which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly defining anddistinctly claiming the invention, it is believed that the inventionwill be better understood from the following description of theaccompanying figures. In the accompanying figures,

FIGS. 1(a) to 1(e) show property analysis of a tooth surface by QuartzCrystal Microbalance with Dissipation monitoring (QCM-D) when the toothsurface is treated according to a specific embodiment of the presentinvention.

FIGS. 2(a) to 2(d) show Scanning Probe Microscopy (SPM) images of atooth surface before treatment, after etching with citric acid, after afirst step of treatment and after a second step of treatment, accordingto a specific embodiment of the present invention.

FIGS. 3(a) to 3(d) show Scanning Probe Microscopy (SPM) images of atooth surface before treatment, after etching with citric acid, after afirst step of treatment and after a second step of treatment, accordingto a comparative embodiment.

FIGS. 4(a) to 4(c) show Scanning Probe Microscopy (SPM) images of atooth surface before treatment, after etching with citric acid, andafter a one-step treatment, according to another comparative embodiment.

FIG. 5 shows panel test results about slick tooth feel over time for 3hours after treatment, according to a specific embodiment of the presentinvention as well as after treatment according to comparativeembodiments.

DETAILED DESCRIPTION OF THE INVENTION

The terms “oral composition” and “oral care composition” are usedinterchangeably herein, and refer to a product, which in the ordinarycourse of usage, is not intentionally swallowed for purposes of systemicadministration of particular therapeutic agents, but is rather retainedin the oral cavity for a time sufficient to contact dental surfacesand/or oral tissues for purposes of topical administration.

The term “dentifrice”, as used herein, includes paste, gel, liquid,powder or tablet formulations for cleaning teeth with the aid of atoothbrush unless otherwise specified. The dentifrice composition may bea single phase composition or may be a combination of two or moreseparate dentifrice compositions.

The term “water-insoluble”, as used herein, means having a lowsolubility in water or being incapable of being fully dissolved inwater. Specifically, a water-insoluble substance is intended to mean asubstance which has a solubility at 20° C. of less than 1 g/l and inparticular of less than 1 mg/l.

The term “water-soluble”, as used herein, means having a high solubilityin water or being capable of being fully dissolved in water.Specifically, a water-soluble substance is intended to mean a substancewhich has a solubility at 20° C. of no less than 1 g/l and in particularof no less than 10 g/l.

The term “particle size”, as used herein, refers to a volume basedparticle size measured by laser diffraction methods. Laser diffractionmeasures particle size distributions by measuring the angular variationin intensity of light scattered as a laser beam passes through adispersed particulate sample. Large particles scatter light at smallangles relative to the laser beam and small particles scatter light atlarge angles. The angular scattering intensity data is then analyzed tocalculate the size of the particles responsible for creating thescattering pattern, using the Mie theory of light scattering. Theparticle size is reported as a volume equivalent sphere diameter. Theterm “mean particle size” and “average particle size” are usedinterchangeably herein, and refer to an average value of particle sizedistribution calculated based on the logarithmic scale.

The terms “hydrocarbyl”, “hydrocarbyl substituent” and “hydrocarbylgroup” are used interchangeably herein, and refer to a univalent radicalhaving a carbon atom directly attached to the remainder of the moleculeand having predominantly hydrocarbon character. Such a univalent radicalcan be classified as an aliphatic group, cyclic group, or combination ofaliphatic and cyclic groups (e.g., alkaryl and aralkyl groups). The term“aliphatic group” means a saturated or unsaturated linear or branchedhydrocarbon group. This term is used to encompass alkyl, alkenyl, andalkynyl groups, for example. The term “alkyl group” means a saturatedlinear or branched hydrocarbon group including, for example, methyl,ethyl, isopropyl, t-butyl, heptyl, dodecyl, octadecyl, amyl,2-ethylhexyl, and the like. The term “alkenyl group” means anunsaturated, linear or branched hydrocarbon group with one or morecarbon-carbon double bonds, such as a vinyl group. The term “alkynylgroup” means an unsaturated, linear or branched hydrocarbon group withone or more carbon-carbon triple bonds. The term “cyclic group” means aclosed ring hydrocarbon group that is classified as an alicyclic group,aromatic group, or heterocyclic group. The term “alicyclic group” meansa cyclic hydrocarbon group having properties resembling those ofaliphatic groups. The term “aromatic group” or “aryl group” means amono- or polynuclear aromatic hydrocarbon group.

The term “viscosity”, as mentioned herein, is measured using Brookfieldviscometers with cone and plate attachment. For viscosities in the rangeof 0-16000 cps, the Brookfield DV-II viscometer with S02 plate is used.A 500 ml sample of the composition is equilibrated at 25° C. for threeminutes before the readings are taken at 2.5 rpm. For viscositiesgreater than 16000 cps and up to 33000 cps, the Brookfield DV-Iviscometer with S02 plate is used. A 500 ml sample of the composition isequilibrated for 1 minute at 25° C. before the readings are taken at 0.3rpm.

The term “tooth” or its plural form “teeth”, as used herein, refers tonatural tooth as well as artificial tooth or dental prosthesis.

Active and other ingredients useful herein may be categorized ordescribed by their cosmetic and/or therapeutic benefit or theirpostulated mode of action or function. However, it is to be understoodthat the active and other ingredients useful herein can, in someinstances, provide more than one cosmetic and/or therapeutic benefit orfunction or operate via more than one mode of action. Therefore,classifications herein are made for the sake of convenience and are notintended to limit an ingredient to the particularly stated applicationor applications listed.

As used herein, the articles including “a” and “an” when used in aclaim, are understood to mean one or more of what is claimed ordescribed.

As used herein, the terms “comprise”, “comprises”, “comprising”,“include”, “includes”, “including”, “contain”, “contains”, and“containing” are meant to be non-limiting, i.e., other steps and othersections which do not affect the end of result can be added. The aboveterms encompass the terms “consisting of” and “consisting essentiallyof”.

As used herein, the words “preferred”, “preferably” and variants referto embodiments of the invention that afford certain benefits, undercertain circumstances. However, other embodiments may also be preferred,under the same or other circumstances. Furthermore, the recitation ofone or more preferred embodiments does not imply that other embodimentsare not useful, and is not intended to exclude other embodiments fromthe scope of the invention.

Sequential Application System

In accordance with the present invention, a sequential applicationsystem is provided to treat the tooth surface.

In the first step (a), the tooth surface is contacted with a firstcomposition comprising a water-insoluble calcium phosphate, wherein thewater-insoluble calcium phosphate has a calcium to phosphorus molarratio from 1:1 to 10:1. The water-insoluble calcium phosphate particlescan deposit into micro-cracks and crevices, providing a source ofcalcium and phosphate ions for remineralization of the dental enamel.

In the second step (b), the tooth surface is further contacted with asecond composition comprising the organophosphate as definedhereinabove. The organophosphate can form a protection layer on thetooth surface so as to seal the calcium and phosphate ions into thetooth structure.

In a specific embodiment, contacting step (b) is initiated within 30minutes, within 15 minutes, within 5 minutes, or immediately after theconclusion of contacting step (a). It is preferred that there is nointervening dental treatment step between step (a) and step (b).

The contacting steps can be achieved by any oral care hygiene regimen,for example, selected from the group consisting of brushing, flossing,rinsing, plastering, attaching, and combinations thereof. Accordingly,the first composition and the second composition can be in various formsto facilitate the oral care hygiene regimen. Such forms include but arenot limited to toothpaste, tooth powder, tooth gel, dental floss, mouthrinse, chewable tablet, chewing gum, or strip or film for directapplication or attachment to the tooth surface. In a specificembodiment, the first composition is a toothpaste composition and thesecond composition is a mouth rinse. In another specific embodiment, thefirst composition and the second composition are each independently amouth rinse.

The contacting duration depends on the specific regimen and the specificcomposition form. For example, brushing with a toothpaste may beconducted from 1 to 5 minutes, rinsing with a mouth rinse may beconducted from 5 seconds to 2 minutes, and plastering with a strip orfilm may be conducted from 5 minutes to 60 minutes, preferably from 20minutes to 40 minutes.

In a specific embodiment, contacting steps (a) and (b) eachindependently has a contacting duration from 5 seconds to 5 minutes; andcontacting step (b) is initiated immediately after the conclusion ofcontacting step (a).

In a specific embodiment, contacting step (a) is achieved by brushingthe tooth surface with a toothpaste comprising the first composition,and then contacting step (b) is immediately achieved by rinsing thetooth surface with a mouth rinse comprising the second composition.

In another specific embodiment, contacting step (a) is achieved byrinsing the tooth surface with a first mouth rinse comprising the firstcomposition, and then contacting step (b) is immediately achieved byrinsing the tooth surface with a second mouth rinse comprising thesecond composition.

The First Composition

Tooth surfaces are constantly experiencing a loss and gain of minerals.This process is partially kept in balance by the chemical composition ofsaliva and the extra-cellular fluid. Disruption of the tooth surfaceintegrity can occur by acidic food and beverages, bacterial challengeand erosion by exaggerated tooth brushing or grinding of the teeth.These processes are accompanied by a demineralization of the exposedtooth surfaces leading to surface roughness. Therefore, according to thepresent invention, the first composition provides a source of calciumand phosphate ions for remineralization of the dental enamel bydepositing into micro-cracks and crevices in the tooth structure or onthe tooth surface.

In a specific embodiment, the first composition comprises awater-insoluble calcium phosphate, wherein the water-insoluble calciumphosphate has a calcium to phosphorus molar ratio from 1:1 to 10:1.

Calcium phosphate is the main mineral found in teeth. Tooth enamel iscomposed of almost ninety percent of hydroxyapatite which is a calciumphosphate mineral known as bone mineral. The water-insoluble calciumphosphate as used in the present invention can release and deliver smallamounts of calcium and phosphate ions under physiological conditions forpromoting remineralization of the tooth enamel.

It has also been found that a specific calcium to phosphorus molar ratiorange is important for tooth health and remineralization of the toothenamel. A ratio of calcium to phosphorus that is too high may not beeffective in inhibiting caries of the crowns and/or tartar on teeth,while one that is too low may not be effective in inhibiting caries nearthe gum and/or may increase inflammatory tendencies such as pyorrhea andgingivitis. In a specific embodiment, the water-insoluble calciumphosphate has a calcium to phosphorus molar ratio from 1:1 to 5:1, orfrom 1:1 to 3:1, or from 1.5:1 to 2.5:1, or from 1.3:1 to 2:1.

Suitable water-insoluble calcium phosphates useful in the presentinvention include, but are not limited to, apatite, calcium halidephosphate, dicalcium phosphate, tricalcium phosphate, octacalciumphosphate, and mixtures thereof. In an embodiment, the apatite isselected from the group consisting of hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂),fluorapatite (Ca₁₀(PO₄)₆F₂), chlorapatite (Ca₁₀(PO₄)₆Cl₂), bromapatite(Ca₁₀(PO₄)₆Br₂) and mixtures thereof.

The water-insoluble calcium phosphate can be in any solid form, forexample, substantially spherical particles, agglomerates of smallerparticles, rod-like particles, needle-like particles, fibroid particlesor mixtures thereof.

The water-insoluble calcium phosphate can be of any size which candeposit onto the tooth surface without impairing the spirit of thepresent invention. In a specific embodiment, the water-insoluble calciumphosphate has a particle size from 0.01, 0.5, 1, 2, or 4 to 5, 8, 10, 15or 20 microns.

According to the present invention, the geometry and size of thewater-insoluble calcium phosphate particles can be optimized so that thevarious micro-cracks or crevices on the tooth surface are taken intoaccount.

The water-insoluble calcium phosphate is present in an amount from0.01%, 0.05%, 0.1%, 0.5%, 1%, or 2% to 3%, 5%, 10%, 20%, 50%, or 99%, byweight, of the first composition. In a specific embodiment, the firstcomposition comprises 0.1% to 20%, by weight, of apatite. In a furtherspecific embodiment, the first composition comprises 1% to 5%, byweight, of hydroxyapatite. The amount of the water-insoluble calciumphosphate can be adjusted to provide the desired technical and sensorialbenefits while mitigating any side effects. In some medical or clinicalcases when the side effects do not matter much, the amount of thewater-insoluble calcium phosphate can be up to 99%, by weight, of thefirst composition.

The pH of the first composition can be in the range from 6, 7, or 8 to9, 10, or 11. The pH can be achieved through a proper balancing of thecalcium phosphate sources or by addition of an alkaline or acidic agent.Without wishing to be bound by theory, a relatively basic pH ispreferred because it is believed to stabilize the water-insolublecalcium phosphate from being dissolved.

The Second Composition

According to the present invention, the second composition comprises aspecific organophosphate compound. The organophosphate compound has astrong affinity for enamel surfaces, like teeth, and has a sufficientsurface binding propensity to desorb pellicle proteins and remainaffixed to enamel surfaces. Without wishing to be bound by any theory,it is believed that, when applied according to the present invention,the organophosphate compound adheres to the teeth, with the phosphategroups binding the calcium in teeth and thus preventing loss of calciumfrom dissolution into acidic saliva. The organophosphate may alsodeposit a protective surface coating that prevents teeth from cominginto direct contact with erosive acids or other harmful substances.

In particular, the second composition comprises an organophosphatehaving the formula:

wherein R is a hydrocarbyl comprising 4 to 22 carbon atoms; X and Y areeach independently an alkylene comprising 2 to 4 carbon atoms; a and bare each independently an integer selected from 0 to 20, and a+b is inthe range from 0 to 20; Z¹ and Z² are each independently selected fromhydrogen, hydrocarbyl comprising 1 to 26 carbons preferably comprisingone or more ether moieties, and a counter ion, provided that at leastone of Z¹ and Z² is hydrogen or a counter ion.

Examples of hydrocarbyl groups useful herein include, but are notlimited to: (1) hydrocarbon substituents, that is, aliphatic (e.g.,alkyl or alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl)substituents, and aromatic-, aliphatic-, and alicyclic-substitutedaromatic substituents, as well as cyclic substituents wherein the ringis completed through another portion of the molecule (e.g., twosubstituents together form an alicyclic radical) and equivalentsthereof; (2) substituted hydrocarbon substituents, that is, substituentscontaining non-hydrocarbon groups which, in the context of thedescription herein, do not alter the predominantly hydrocarbonsubstituent (e.g., halo (especially chloro and fluoro), hydroxy, alkoxy,mercapto, alkylmercapto, nitro, nitroso, and sulfoxy) and equivalentsthereof; (3) hetero-substituents, that is, substituents which, whilehaving a predominantly hydrocarbon character, in the context of thisdescription, contain other than carbon in a ring or chain otherwisecomposed of carbon atoms and equivalents thereof. Hetero-atoms includesulfur, oxygen, nitrogen, and encompass substituents such as pyridyl,furyl, thienyl and imidazolyl. In a specific embodiment, no more thantwo, preferably no more than one, non-hydrocarbon substituent is presentfor every ten carbon atoms in the hydrocarbyl group. In a furtherspecific embodiment, there is no non-hydrocarbon substituent in thehydrocarbyl group.

The presence of the hydrocarbyl group is believed to impart to thecompound a degree of hydrophobicity, so that the organophosphate caneffectively form a hydrophobic layer on the tooth surface. Such ahydrophobic layer can protect the enamel from erosive acidic challengesand stain deposition, and provide good smooth feeling for a prolongedtime.

Some examples of the organophosphate include, but are not limited to,alkyl phosphates and alkyl (poly)alkoxy phosphates, such as laurylphosphate (tradenames MAP 230K and MAP 230T commercially available fromCroda, Snaith, UK); PPG5 ceteareth-10 phosphate (Crodaphos SGcommercially available from Croda, Snaith, UK); laureth-1 phosphate(tradenames MAP L210 commercially available from Rhodia, La Défense,France, Phosten HLP-1 commercially available from Nikkol Chemical,Tokyo, Japan, or Sunmaep L commercially available from Sunjin Chemical,Korea); laureth-3 phosphate (tradenames MAP L130 commercially availablefrom Rhodia, La Défense, France, Foamphos L-3 commercially availablefrom Alzo, NJ, U.S., or Emphiphos DF 1326 commercially available fromHuntsman Chemical, Texas, U.S.); laureth-9 phosphate (tradename FoamphosL-9 commercially available from Alzo, NJ, U.S.); trilaureth-4 phosphate(tradenames Hostaphat KL 340D commercially available from Clariant,Muttenz, Switzerland, or TLP-4 commercially available from NikkolChemical, Tokyo, Japan); C12-18 PEG 9 phosphate (tradename Crafol AP261commercially available from Cognis, Ludwigshafen, Germany); sodiumdilaureth-10 phosphate (tradename DLP-10 commercially available fromNikkol Chemical, Tokyo, Japan).

Particularly preferred organophosphates are those containing alkoxygroups, especially repeating alkoxy groups, (O—X)_(a)(O—Y)_(b), inparticular those containing 1 or more ethoxy, propoxy, isopropoxy,butoxy groups or combinations thereof. The presence of the alkoxy groupis believed to increase the solubility of the compound and balance theamphiphilicity of the compound, so that the hydrophilic phosphate headcan “stick” to the tooth surface (given its charge) while thehydrophobic hydrocarbyl tail is extended to a long carbon chain. On theother hand, the presence of the alkoxy group can help diffusingsubstances away from the tooth surface.

Additional suitable organophosphates may include alkyl mono glyceridephosphate, alkyl sorbitan phosphate, alkyl methyl glucoside phosphate,alkyl sucrose phosphates, dextran phosphate, polyglucoside phosphate,alkyl polyglucoside phosphate, polyglyceryl phosphate, alkylpolyglyceryl phosphate, polyether phosphates and alkoxylated polyolphosphates. Some specific examples may include polyethylene glycol (PEG)phosphate, polypropylene glycol (PPG) phosphate, alkyl PPG phosphate,PEG/PPG phosphate, alkyl PEG/PPG phosphate, PEG/PPG/PEG phosphate,dipropylene glycol phosphate, PEG glyceryl phosphate, polybutyleneglycol (PBG) phosphate, PEG cyclodextrin phosphate, PEG sorbitanphosphate, PEG alkyl sorbitan phosphate, PEG methyl glucoside phosphate,and combinations thereof.

The organophosphate may provide desired surface conditioning effectsincluding: 1) effective desorption of undesirably adsorbed pellicleproteins, in particular those associated with tooth stain binding,calculus development and attraction of undesirable microbial species,and 2) maintaining surface conditioning effects and control of pelliclefilm formation for extended periods following product use. The presentcompositions provide a protective surface coating by binding calciumminerals within teeth (e.g., hydroxyapatite). The protective surfacecoating provides improved tooth surface characteristics by modifyingsurface hydrophilic and hydrophobic properties and improving resistanceto dietary acid attack.

The amount of the organophosphate in the second composition is aneffective amount to provide the protection layer with good smoothfeeling for some desired time. Preferably, the protection will last forat least an hour after use of the composition. The organophosphate canbe present in an amount effective to provide an increase of at least 10degrees in water contact angle on the surface, with the hydrophobiccharacter being maintained for a period of at least 5 minutes. In aspecific embodiment, the organophosphate is present in an amount rangingfrom 0.01%, 0.02%, 0.03%, 0.05%, 0.07%, or 0.1% to 0.5%, 1%, 5%, 10%,50%, or 99%, by weight, of the second composition. The amount of theorganophosphate can be adjusted to provide the desired technical andsensorial benefits while mitigating any side effects which theorganophosphate compound may have, for example, an undesirable bitter orsoapy taste. In some medical or clinical cases when the undesirablebitter or soapy taste is not a big consideration, the amount of theorganophosphate can be up to 99%, by weight, of the second composition.

In a specific embodiment, the organophosphate is defined by: R is analkyl comprising 8 to 16 carbon atoms; a+b is from 1 to 10; and Z¹ andZ² are each independently selected from the group consisting of hydrogenand an alkali metal counter ion. Preferably, at least one of Z¹ and Z²is an alkali metal counter ion selected from the group consisting ofsodium ion and potassium ion; and wherein the second compositioncomprises 0.01% to 10%, by weight, of the organophosphate.

Specifically, the organophosphate can be selected from the groupconsisting of sodium laureth-1 phosphate, sodium laureth-2 phosphate,sodium laureth-3 phosphate, sodium laureth-4 phosphate, potassiumlaureth-1 phosphate, sodium laureth-9 phosphate, sodium myreth-2phosphate, sodium pareth-1 phosphate and mixtures thereof.

In a specific embodiment, the second composition comprises 0.01% or0.05% to 5% or 10%, by weight, of sodium laureth-1 phosphate.

The pH of the second composition can be in the range from 5, 6, or 6.5to 7.5, 8 or 10. The pH of the second composition should not be too lowsince there is a possibility of the organophosphate hydrolyzing in astrong acidic environment.

Optional Components

The first composition and the second composition of the presentinvention can each independently contain a variety of optionalconventional components useful in oral compositions to increase thebenefits mentioned herein or provide additional benefits. Such optionalcomponents include, but are not limited to, a fluoride ion source, athickening agent, a humectant, a surfactant, an antibacterial agent, acolorant, a flavorant, and some other conventional components.

A fluoride ion source, also called a water-soluble fluoride source,capable of providing free fluoride ions, can help acceleratingremineralization by increasing local supersaturation with respect tofluoridated calcium phosphate deposition. Fluoride uptake orfluoridation refers to the acquisition of fluoride into tooth substratesresulting from topical treatments with fluoride agents. Teeth withincreased remineralization and fluoride uptake exhibit superiorresistance to acid demineralization and therefore help prolong thesmoothing effect on the tooth surface. The water-soluble fluoride sourcecan be selected from the group consisting of sodium fluoride, stannousfluoride, sodium monofluorophosphate, amine fluoride, and mixturesthereof. In a specific embodiment, the second composition comprises awater-soluble fluoride source capable of providing from 50 ppm, 500 ppm,1000 ppm, or 1500 ppm to 2000 ppm, 2500 ppm, 3000 ppm, or 3500 ppm offree fluoride ions. In a further specific embodiment, the secondcomposition comprises 0.005%, 0.01%, or 0.02% to 0.1%, 1%, or 5%, byweight, of sodium fluoride. In an even further specific embodiment, thefirst composition comprises 1% to 5%, by weight, of hydroxyapatite, andthe second composition comprises 0.05% to 5%, by weight, of sodiumlaureth-1 phosphate and 0.01% to 1%, by weight, of sodium fluoride.

Thickening agents, also called thickeners, are generally used toincrease the viscosity of a solution or liquid/solid mixture. Accordingto the present invention, thickening agents can be incorporated toprovide a consumer desirable consistency and tooth coating ability byadjusting the viscosity of the composition. The oral care composition ofthe present invention can have a viscosity ranging from 10 cps, 50 cps,100 cps, 500 cps, 800 cps, 1200 cps, or 2000 cps to 3000 cps, 5000 cps,8000 cps, 12000 cps, 20000 cps, 30000 cps, or 45000 cps, depending onthe delivery form of the composition. In a specific embodiment, thefirst composition has a viscosity of 2000 cps to 8000 cps. In anotherspecific embodiment, the second composition has a viscosity of 1200 cpsto 3000 cps. Thicker composition tends to provide longer lastingbenefits on the tooth surface. Thickening agents may also improve thesuspension of insoluble ingredients to provide a stable and uniformcomposition. This is especially advantageous when the first compositioncomprising the water-insoluble calcium phosphate is a mouth rinse.Preferred thickening agents are selected from the group consisting ofcarboxyvinyl polymers, carrageenan, xanthan gum, cellulosic polymers,hydroxyethyl cellulose, carboxymethyl cellulose, ammoniumacryloyldimethyltaurate/vinylprrolidone copolymer, polyethylene oxide,acrylates/C10-30 alkyl acrylate crosspolymer, polyacrylic acid,cross-linked polyacrylic acid, polycarbophil, alginate, clay, glucose,pectin, gelatin, and combinations thereof. Colloidal magnesium aluminumsilicate or finely divided silica can also be used as part of thethickening agent to further improve texture. The thickening agent can bepresent in an amount from 0.01%, 0.1%, 0.2%, 0.3%, or 0.4% to 2%, 5%,8%, 10%, or 20%, by weight, of the first composition or the secondcomposition.

Humectants such as polyethylene glycols can also been used to modifyviscosity and to provide a smooth feel to dentifrice compositions.Polyethylene glycols are available in a large range of average molecularweights and have different properties depending upon their averagemolecular weights. The humectant serves to keep the oral composition,especially a toothpaste composition, from hardening upon exposure to airand give a moist feel to the mouth. Certain humectants can also impart adesirable sweet flavor to oral compositions such as mouth rinse andtoothpaste. Suitable humectants for use in the present invention includeedible polyhydric alcohols such as glycerin, sorbitol, xylitol, butyleneglycol, polyethylene glycol, propylene glycol, and mixtures thereof. Thehumectant is optionally present in an amount of 1%, 2%, 5%, or 8% to15%, 25%, 50%, or 70%, by weight, of the first composition or the secondcomposition.

Surfactants are useful, for example, to make other components of theoral care composition more compatible with one another. This providesenhanced stability, helps in cleaning the dental surface throughdetergency, and provides foam upon agitation, e.g., during brushing witha dentifrice composition of the invention. Any orally acceptablesurfactant, most of which are anionic, nonionic or amphoteric, can beused. Suitable anionic surfactants include without limitationwater-soluble salts of C8-20 alkyl sulfates, sulfonated monoglyceridesof C8-20 fatty acids, sarcosinates, taurates and the like. Illustrativeexamples of these and other classes include sodium lauryl sulfate,sodium coconut monoglyceride sulfonate, sodium lauryl sarcosinate,sodium lauryl isoethionate, sodium laureth carboxylate and sodiumdodecyl benzenesulfonate. Suitable nonionic surfactants include withoutlimitation poloxamers, polyoxyethylene sorbitan esters, fatty alcoholethoxylates, alkylphenol ethoxylates, tertiary amine oxides, tertiaryphosphine oxides, dialkyl sulfoxides and the like. Suitable amphotericsurfactants include without limitation derivatives of C8-20 aliphaticsecondary and tertiary amines having an anionic group such ascarboxylate, sulfate, sulfonate, phosphate or phosphonate. A suitableexample is cocoamidopropyl betaine. The surfactant is optionally presentin an amount of 0.01%, 0.05%, or 0.1% to 2%, 5%, or 10%, by weight, ofthe first composition or the second composition.

Antibacterial agents useful in the present invention include but are notlimited to water insoluble non-cationic antibacterial agents and watersoluble antibacterial agents such as quaternary ammonium salts andbis-biquanide salts. Triclosan monophosphate is an additional watersoluble antibacterial agent. In some preferred embodiments, theantibacterial agent is selected from the group consisting ofcetylpyridinium halide, domiphen halide, a stannous ion source, a zincion source, a copper ion source, and mixtures thereof. Theseantibacterial agents may be present at levels of from 0.01%, 0.05%,0.1%, or 0.2% to 0.5%, 1.0%, 1.2% or 1.5%, by weight, of the firstcomposition or the second composition.

Colorants herein include pigments, dyes, lakes and agents imparting aparticular luster or reflectivity such as pearling agents. A colorantcan serve a number of functions, including for example to provide awhite or light-colored coating on a dental surface, to act as anindicator of locations on a dental surface that have been effectivelycontacted by the composition, and/or to modify appearance, in particularcolor and/or opacity, of the composition to enhance attractiveness tothe user. Any orally acceptable colorant can be used, including but notlimited to talc, mica, magnesium carbonate, calcium carbonate, magnesiumsilicate, magnesium aluminum silicate, silica, titanium dioxide, zincoxide, red, yellow, brown and black iron oxides, ferric ammoniumferrocyanide, manganese violet, ultramarine, titaniated mica, bismuthoxychloride and the like.

Flavorants are useful for example to enhance taste of the composition.Any orally acceptable natural or synthetic flavorant can be used,including but not limited to vanillin, sage, marjoram, parsley oil,spearmint oil, cinnamon oil, oil of wintergreen (methylsalicylate),peppermint oil, clove oil, bay oil, anise oil, eucalyptus oil, citrusoils, fruit oils and essences including those derived from lemon,orange, lime, grapefruit, apricot, banana, grape, apple, strawberry,cherry, pineapple, etc., bean- and nut-derived flavors such as coffee,cocoa, cola, peanut, almond, etc., adsorbed and encapsulated flavorantsand the like. Also encompassed within flavorants herein are ingredientsthat provide fragrance and/or other sensory effect in the mouth,including cooling or warming effects. Such ingredients illustrativelyinclude menthol, menthyl acetate, menthyl lactate, camphor, eucalyptusoil, eucalyptol, anethole, eugenol, cassia, oxanone, α-irisone, propenylguaiethol, thymol, linalool, benzaldehyde, cinnamaldehyde,N-ethyl-p-menthan-3-carboxamine, N,2,3-trimethyl-2-isopropylbutanamide,3-(1-menthoxy)-propane-1,2-diol, cinnamaldehyde glycerol acetal (CGA),menthone glycerol acetal (MGA) and the like.

Oral Care Kit and Product

The present invention also provides any form of kit and productcomprising the first composition and the second composition as discussedabove.

In some embodiments, the oral care kit comprises:

(a) a first product containing a first composition, wherein the firstcomposition comprises 0.01% to 99%, by weight, of a water-insolublecalcium phosphate having a calcium to phosphorus molar ratio from 1:1 to10:1;

(b) a second product containing a second composition, wherein the secondproduct is a mouth rinse with a pH from 6 to 8 and a viscosity from 100cps to 5000 cps, and wherein the second composition comprises 0.01% to99%, by weight, of an organophosphate as defined above; and

(c) instructions instructing a user to first use the first product tocontact a tooth surface and thereafter immediately use the secondproduct to contact the tooth surface.

In some embodiments, the kit further includes an applicator to apply thefirst and/or second compositions to the tooth surface, for example, asyringe-type applicator for depositing a composition on the toothsurface or an applicator in the shape of a semicircular trough for usein applying composition to the tooth surface. The kit may alsooptionally include instructions on the use of an applicator in applyingthe composition to a tooth surface.

In a specific embodiment, the first product and the second product canbe physically separated, each independently as any suitable form, forexample, as a liquid form or a dry powder. When the composition providedis a dry powder, the composition may be reconstituted by the addition ofa suitable solvent, which may also be included in the kit. Inembodiments where a liquid form is provided, the composition may beconcentrated or ready to use.

In a specific embodiment, the first product and the second product areeach independently a mouth rinse.

In some embodiments, the present invention intends to provide a singleoral care product comprising a first container and a second container,wherein the first container contains a first composition comprising0.01% to 99%, by weight, of a water-insoluble calcium phosphate whichhas a calcium to phosphorus molar ratio from 1:1 to 10:1, and the secondcontainer contains a second composition comprising 0.01% to 99%, byweight, of an organophosphate as defined above. The product mayoptionally contain instructions instructing a user to dispense the firstcomposition before the second composition is dispensed.

In a specific embodiment, the single oral care product further comprisesinstructions instructing a user to first dispense the first compositionfrom the first container to contact a tooth surface and thereafterdispense the second composition from the second container to contact thetooth surface for every use.

In another specific embodiment, the single oral care product furthercomprises a pump which pumps the first composition from the firstcontainer upon a first actuation and pumps the second composition fromthe second container upon a second actuation for every treatment regimenuse.

Examples

The following examples further describe and demonstrate embodimentswithin the scope of the present invention. These examples are givensolely for the purpose of illustration and are not meant to be construedas limitations of the present invention, as many variations thereof arepossible without departing from the spirit and scope of the presentinvention.

The First Composition

Table 1 shows examples of the first composition according to the presentinvention in the form of mouth rinses. The preparation process is asfollows: add glycerin and polymers to a first mixing vessel, mixinguntil well dispersed to get Premix 1; add water (10% of the totalamount), flavors & sensates, hydroxyapatite, sweeteners, liquidpreservatives, surfactants, and colorants & aesthetics to a secondmixing vessel, mixing until well dispersed and homogenous to get Premix2; add water (90% of the total amount), solid preservatives, andthickening agents to a main mixing tank, mixing until homogenous to geta main mix; add Premix 1 to the main mix, mixing until well dispersed;add 25% of the total sodium hydroxide (if applicable) to the main mix,mixing until homogenous; add Premix 2 to the main mix, mixing until welldispersed and homogenous; and add the rest of the sodium hydroxide untilthe pH is 7.

TABLE 1 Ingredients A1 A2 A3 A4 A5 A6 A7 A8 Water 77.744 77.674 75.24479.244 76.279 78.404 77.654 79.154 Glycerin 18.000 18.000 18.000 18.00018.000 18.000 18.000 18.000 Methylparaben 0.020 0.020 0.020 0.020 0.0200.020 0.020 0.020 Propylparaben 0.005 0.005 0.005 0.005 0.005 0.0050.005 0.005 Benzyl Alcohol 1.000 0.900 1.000 1.000 0.900 0.900 0.9000.900 Aristoflex AVC 0.500 — 0.500 0.500 — — — — Carbopol ETD2020 —0.200 — — 0.250 0.125 0.125 0.125 Polyox WSR1105 — 0.200 — — 1.000 0.5000.500 0.500 Vitamin E Acetate — 0.070 — — 0.070 0.070 0.070 0.070Bio-Gel HTP¹⁾ 2.500 — 5.000 1.000 — — — — nanoXIM.Care powder²⁾ — 2.500— — 3.000 1.500 2.250 0.750 Sodium Saccharin 0.013 0.013 0.013 0.0130.013 0.013 0.013 0.013 Sucralose 0.008 0.008 0.008 0.008 0.008 0.0080.008 0.008 Peppermint 92 180 Blend 0.100 — 0.100 0.100 — — — —Starburst Peppermint — 0.100 — — 0.120 0.120 0.120 0.120 SodiumHydroxide — 0.200 0.200 0.200 0.200 0.200 Titanium Dioxide 0.100 0.1000.100 0.100 0.050 0.050 0.050 0.050 Poloxamer 407 0.010 0.010 0.0100.010 0.010 0.010 0.010 0.010 Candurin Silver Lustre — — — — 0.075 0.0750.075 0.075 Total 100 100 100 100 100 100 100 100 ¹⁾Hydroxyapatitesupplied by Bio-Rad, Hercules, CA, USA ²⁾Hydroxyapatite supplied byFluidinova, Moreira da Maia, Portugal

As a mouth rinse, appropriate viscosity will suspend the hydroxyapatiteuniformly in the composition and facilitate proper contact and retentionof the composition on the tooth surface. The first compositions, A1 toA8, have a viscosity of 2580 cps, 7690 cps, 5072 cps, 2600 cps, 29433cps, 132 cps, 220 cps, and 116 cps, respectively.

Table 2 shows examples of the first composition according to the presentinvention in the form of toothpastes. The preparation process is asfollows: add water, humectants, part of flavor, colorant, buffer andactive to a main mixing tank of 35° C., mixing well and ensuring all theingredients have dissolved or been well dispersed; add thickening agentsand sweetener into the main mixing tank, mixing and homogenizing untilwell dispersed and homogeneous; add abrasives, mixing and homogenizinguntil well dispersed and homogeneous; deaerate; add surfactant solution,rest part of flavor to the main mixing tank, mixing and homogenizinguntil homogeneous; de-aerate; pump out and cool the batch to less than40° C.

TABLE 2 Ingredients A9 A10 A11 A12 A13 Sorbitol solution (70%) 22.16940.370 40.500 — 23.000 Sodium fluoride 0.321 0.234 — — — Water purified45.000 33.096 22.950 — 44.170 Silica abrasive 15.000 12.500 17.00017.000 15.000 Sodium Lauryl 7.000 5.000 5.000 3.500 5.000 Sulfate (28%)Sodium Carboxymethyl 1.400 1.300 1.300 — 1.500 Cellulose Carrageenan —0.700 0.700 0.600 — Carbomer 956 0.400 — — — 0.500 Sodium saccharin0.280 0.300 0.300 0.300 0.280 Xanthan gum 0.250 — — 0.250 0.250 Titaniumdioxide 0.250 0.500 0.525 0.400 0.250 Flavor 0.900 1.000 0.900 1.0001.000 Sodium hydroxide 32% 3.750 — — 3.750 Mica 0.280 — — 0.500 0.300Bio-Gel HTP¹⁾ 3.000 7.500 5.000 nanoXIM.Care powder²⁾ 5.000 10.000Glycerin — — — 41.950 — Sodium polyphosphate — — — 13.000 — Sodiumcitrate — — 0.150 — — Sodium gluconate — 1.064 — — — Zinc citrate —0.955 0.375 — — Hydroxyethyl Cellulose — 0.300 0.300 — — Stannouschloride — 1.160 — — — Propylene glycol — — — 7.000 — Polyethyleneglycol — — — 7.000 — Total 100 100 100 100 100 ¹⁾Hydroxyapatite suppliedby Bio-Rad, Hercules, CA, USA ²⁾Hydroxyapatite supplied by Fluidinova,Moreira da Maia, Portugal

The Second Composition

Table 3 shows examples of the second composition according to thepresent invention in the form of mouth rinses. The preparation processis the same as that for the first compositions in the form of mouthrinses, except that no hydroxyapatite is added in the Premix 2 and thatsodium fluoride and organophosphate are added along with water (90% ofthe total amount), solid preservatives, and thickening agents to get amain mix.

TABLE 3 Ingredients B1 B2 B3 B4 B5 B6 B7 Water 80.014 80.144 79.91479.729 79.364 79.794 79.704 Glycerin 18.000 18.000 18.000 18.000 18.00018.000 18.000 Methylparaben 0.020 0.020 0.020 0.020 0.020 0.020 0.020Propylparaben 0.005 0.005 0.005 0.005 0.005 0.005 0.005 Benzyl Alcohol1.000 0.900 1.000 0.900 0.800 0.900 0.900 Aristoflex AVC 0.400 — 0.500 —— — — Carbopol ETD2020 — 0.150 — 0.150 0.350 0.200 0.175 Polyox WSR1105— — — 0.200 0.150 0.200 0.200 Vitamin E Acetate — 0.070 — 0.070 0.0700.070 0.070 Sodium Fluoride — 0.050 — 0.020 0.050 0.050 0.020 MAPL213S³⁾ 0.330 — 0.330 0.660 — 0.330 Foamphos L-9⁴⁾ — 0.330 0.330 — 0.330— Sodium Saccharin 0.013 0.013 0.013 0.013 0.013 0.013 0.013 Sucralose0.008 0.008 0.008 0.008 0.008 0.008 0.008 Peppermint 92 180 Blend 0.100— 0.100 0.100 0.100 — 0.100 Starburst Peppermint — — — — — 0.100 — PolarMint Diluted — — — 0.120 — — 0.120 Sodium Hydroxide — 0.200 — 0.2000.200 0.200 0.200 Titanium Dioxide 0.100 0.100 0.100 0.050 0.100 0.1000.050 Candurin Silver Lustre — — — 0.075 — — 0.075 Timica Extra Bright —— — — 0.100 — — Poloxamer 407 0.010 0.010 0.010 0.010 0.010 0.010 0.010Total 100 100 100 100 100 100 100 ³⁾Laureth-1 phosphate supplied byRhodia, pre-neutralized ⁴⁾Laureth-9 phosphate supplied by Alzo,neutralized with NaOH

The second compositions, B3 to B7, have a viscosity of 3072 cps, 1376cps, 216.5 cps, 1408 cps, and 2616 cps, respectively. B1 and B2 are notmeasured.

Table 4 shows examples of the second composition according to thepresent invention in the form of nonabrasive tooth gels. Preparationprocess is as follows: add mineral oil/petrolatum/Versagel, humectants,part of flavor, and colorant to a main mixing tank of 35° C., mixingwell and ensuring all the ingredients have dissolved or been welldispersed; add organophosphate and sweetener into the main mixing tank,mixing and homogenizing until well dispersed and homogeneous; deaerate;add surfactant solution, rest part of flavor to the main mixing tank,mixing and homogenizing until homogeneous; deaerate; pump out and coolthe batch to less than 40° C.

TABLE 4 Ingredients B8 B9 B10 B11 B12 MAP L-130⁵⁾ 13.330 — — — —Foamphos L-3⁶⁾ — 8.000 — — — MAP 230K⁷⁾ — — 10.000 — — DLP-10⁸⁾ — — —5.000 — Crodaphos SG⁹⁾ — — — — 2.000 Glycerin 20.000 13.000 22.00035.000 — Flavor 2.000 2.000 2.000 2.000 1.000 Saccharin 0.500 0.5000.500 0.500 2.000 Polyethylene oxide 2.000 2.000 2.000 2.000 — Carbomer956 0.500 0.500 0.500 0.500 — Mineral Oil — — — 55.000 — Petrolatum61.670 64.000 63.000 — — Versagel — — — — 95.000 Total 100 100 100 100100 ⁵⁾Laureth-3 phosphate supplied by Rhodia, neutralized with NaOH⁶⁾Laureth-3 phosphate supplied by Alzo, neutralized with NaOH⁷⁾Potassium C12/13 phosphate supplied by Croda ⁸⁾Sodium diLaureth-10phosphate supplied by Nikkol Chemical ⁹⁾PPG5 Ceteareth-10 phosphatesupplied by Croda, neutralized with NaOH

Sequential Application System

One of the first compositions as shown in Tables 1 and 2 and one of thesecond compositions as shown in Tables 3 and 4 can be combined into asequential oral application treatment regimen. Examples of sequentialcompositions according to the present invention are shown in Table 5.

TABLE 5 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 The first compositionA2 A3 A5 A7 A9 A11 A12 The second B6 B8 B1 B10 B3 B7 B12 composition

The compositions in the form of mouth rinses are applied to the toothsurface by swishing and gargling 20 ml of the mouth rinse in the mouthfor 30 seconds and then spitting out. In the application where thesubject composition is too viscous or too thick to be swished or gargledin the mouth, suitable applicators such as a swab can be used to apply(e.g., spread or daub) the composition onto the tooth surface.

The compositions in the form of toothpastes are applied to the toothsurface by brushing with a toothbrush for 2 minutes.

The compositions in the form of tooth gels are applied to the toothsurface by applying the gels evenly into a mouth tray and putting themouth tray onto the teeth for 10 minutes.

Efficacy Measurement

Quartz Crystal Microbalance with Dissipation Monitoring (QCM-D)

QCM-D is a very sensitive mass balance technique allowing simultaneousmeasurement of adsorption kinetics and viscoelastic properties of anadsorbing layer.

In QCM-D, a quartz crystal is excited to oscillate at its fundamentalresonant frequency by the application of AC voltage across the crystal.A material adsorbed onto the surface of the crystal causes the resonantfrequency to change, which is proportional to the mass of the adsorbedfilm.

The damping/dissipation of the crystal's oscillation by the film can bemeasured, allowing for the determination of the viscoelasticity of thefilm.

ΔD=E _(dissipation)/2πE _(stored)

wherein D is the energy dissipated per oscillation divided by the totalenergy stored in the crystal.

A large value for AD indicates that a soft, easily deformed material isattached to the crystal. A rigid material leads to a small AD.

FIGS. 1(a) to 1(e) show the QCM-D data for a tooth surface treated withEx. 1 of the present invention.

Three steps, in sequential order, are followed to treat the test toothsurface. The first step is to rinse the tooth surface with deionizedwater. The second step is to rinse the tooth surface with the firstcomposition, A2. The third step is to further rinse the tooth surfacewith the second composition, B6. The three columns in each of FIGS. 1(a)to 1(e) represent the QCM-D test results after each step.

It can be seen from the QCM-D data that, before the treatment accordingto the present invention, no adsorbed layer is formed on the toothsurface. After treatment with the first composition, a layer displayingviscoelastic properties is adsorbed onto the tooth surface. Afterfurther treatment with the second composition, the adsorbed layer isstrengthened by increased mass, density, and thickness.

Scanning Probe Microscopy (SPM)

Scanning probe microscopy is used to produce topographic images of asurface with nano-scale resolution. In this technique, the deflection ofa microfabricated cantilever spring is monitored as it is raster scannedover the surface in question. Surface roughness analysis allows forquantitative measurements of topographical features as a function ofsurface modification.

FIGS. 2(a) to 2(d) show the changes of an enamel surface when it istreated with Ex. 1 of the present invention. FIG. 2(a) shows a roughenamel surface prior to treatment (i.e., control). FIG. 2(b) shows thatthe enamel surface is further roughened by being etched with citricacid. FIG. 2(c) shows a slightly smoother enamel surface but with someinsoluble components (large particles) deposited after the treatmentwith the first composition, A2. It is believed that the hydroxyapatitehas been deposited onto the surface. FIG. 1(d) shows a smooth enamelsurface after subsequent treatment with the second composition, B6.

In comparison, FIGS. 3(a) to 3(d) show the enamel surface changes whentreated with the same compositions in Ex. 1 of the present invention butin a different sequence. In other words, the comparative enamel surfaceis treated by the second composition, B6, followed by the firstcomposition, A2. FIG. 3(a) shows a rough enamel surface prior totreatment (i.e., control). FIG. 3(b) shows a similarly roughened enamelsurface as FIG. 2(b) after being etched with citric acid. FIG. 3(c)shows a much smoother enamel surface than FIG. 2(c) after the treatmentwith the second composition, B6. However, after the two-step treatmentof the second composition, B6, followed by the first composition, A2,FIG. 3(d) shows an enamel surface rougher than that shown in FIG. 2(d).In FIG. 3(d), the raised or depressed areas can be up to a depth of 20nm, compared to only 10 nm in FIG. 2(d).

SPM images are also taken to show the enamel surface changes after aregular treatment with an Oral B® Pro-Expert dentifrice (produced onMar. 18, 2011 in the US). The Oral B® Pro-Expert dentifrice does notcontain the first composition or the second composition as defined inthe present invention. FIG. 4(a) shows a rough enamel surface prior totreatment. FIG. 4(b) shows a further roughened enamel surface by beingetched with citric acid. FIG. 4(c) shows the enamel surface after thedentifrice treatment, which is almost as rough as the etched enamelsurface. It can be seen that the dentifrice treatment hardly changes theenamel surface smoothness.

Overall, SPM data shows that the treatment according to the presentinvention makes the tooth surface much smoother.

Sensory Panel Test (DPP)

A sensory panel test for slick tooth feeling is conducted by aDescriptive Profile Panel (DPP) comprised of 10 individuals who havebeen screened for above average sensory acuity and ability to describesensations of slick tooth feeling. The panelists are trained on oralcare product specific attributes via Spectrum™ methodology and have theunique ability to evaluate oral care products on an attribute byattribute basis without regard to personal preference or bias. In thistest, panelists use the products as directed and evaluate the productsagainst their standard 3 hour clean mouth feel ballot (including a slickteeth measure) for 3 hours after use. Panelists also provide descriptiveanalysis and additional voluntary comments to call out any other sensoryattributes. Each attribute is measured on a 0-30 scale with definedintervals that are no longer then 15 minutes. After the first hour,panelists drink 8 oz/236.59 mL of a carbonated beverage (one ofCoca-Cola®, Caffeine Free Coca-Cola®, Diet Coke®, and Caffeine Free DietCoke®) with continued evaluation.

The products involved in this panel test include: the first composition(A2) only; the second composition (B6) only; a sequential applicationsystem of A2 followed by B6 according to Ex. 1 of the present invention;a sequential application system of B6 followed by A2; and BioRepair®mouthwash (containing a hydroxyapatite variant, produced on Jun. 11,2011 in British).

As shown in FIG. 5, the sequential application system of A2 followed byB6 according to the present invention provides the best slick tooth feelover time. Although the sequential application system of B6 followed byA2 provides a comparable slick tooth feel immediately after thetreatment, the values for slick tooth feel drop down quickly within 10minutes after the treatment. 20 minutes after the sequential treatmentof B6 followed by A2, the values for slick tooth feel is much lower thanthose obtained by the sequential treatment according to the presentinvention, and even lower than those obtained by individual treatmentwith A2 or B6 only.

BioRepair® mouthwash is a commercial product comprising zinchydroxyapatite. It can be seen from FIG. 5 that both the immediate andthe long-lasting slick tooth feel evaluations are well below thoseobtained by the sequential treatment according to the present invention.

Unless otherwise indicated, all percentages, ratios, and proportions arecalculated based on the weight of the total composition. Alltemperatures are in degrees Celsius (° C.) unless otherwise indicated.All measurements made are at 25° C., unless otherwise designated. Allcomponent or composition levels are in reference to the active level ofthat component or composition, and are exclusive of impurities, forexample, residual solvents or by-products, which may be present incommercially available sources.

It should be understood that every maximum numerical limitation giventhroughout this specification includes every lower numerical limitation,as if such lower numerical limitations were expressly written herein.Every minimum numerical limitation given throughout this specificationwill include every higher numerical limitation, as if such highernumerical limitations were expressly written herein. Every numericalrange given throughout this specification will include every narrowernumerical range that falls within such broader numerical range, as ifsuch narrower numerical ranges were all expressly written herein.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

Every document cited herein, including any cross referenced or relatedpatent or application and any patent application or patent to which thisapplication claims priority or benefit thereof, is hereby incorporatedherein by reference in its entirety unless expressly excluded orotherwise limited. The citation of any document is not an admission thatit is prior art with respect to any invention disclosed or claimedherein or that it alone, or in any combination with any other referenceor references, teaches, suggests or discloses any such invention.Further, to the extent that any meaning or definition of a term in thisdocument conflicts with any meaning or definition of the same term in adocument incorporated by reference, the meaning or definition assignedto that term in this document shall govern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

1. A method of treating a tooth surface comprising the steps: (a)contacting the tooth surface with a first composition comprising awater-insoluble calcium phosphate, wherein the water-insoluble calciumphosphate has a calcium to phosphorus molar ratio from 1:1 to 10:1; andthereafter (b) contacting the tooth surface with a second composition,wherein the second composition comprises an organophosphate having theformula:

wherein R is a hydrocarbyl comprising 4 to 22 carbon atoms; X and Y areeach independently an alkylene comprising 2 to 4 carbon atoms; a and bare each independently an integer selected from 0 to 20, and a+b is inthe range from 0 to 20; Z¹ and Z² are each independently selected fromhydrogen, hydrocarbyl comprising 1 to 26 carbons, and a counter ion,provided that at least one of Z¹ and Z² is hydrogen or a counter ion. 2.The method of claim 1, wherein the contacting step (b) is initiatedwithin 15 minutes after the conclusion of contacting step (a).
 3. Themethod of claim 2, wherein the water-insoluble calcium phosphate isselected from the group consisting of apatite, calcium halide phosphate,dicalcium phosphate, tricalcium phosphate, octacalcium phosphate, andmixtures thereof.
 4. The method of claim 3, wherein the firstcomposition comprises 0.1% to 20% by weight of apatite.
 5. The method ofclaim 4, wherein the first composition comprises 1% to 5% by weight ofhydroxyapatite.
 6. The method of claim 2, wherein the organophosphate isdefined by: R is an alkyl comprising 8 to 16 carbon atoms; a+b is from 1to 10; and Z¹ and Z² are each independently selected from the groupconsisting of hydrogen and an alkali metal counter ion.
 7. The method ofclaim 6, wherein at least one of Z¹ and Z² is an alkali metal counterion selected from the group consisting of sodium ion and potassium ion;and wherein the second composition comprises 0.01% to 10% by weight ofthe organophosphate.
 8. The method of claim 7, wherein theorganophosphate is selected from the group consisting of sodiumlaureth-1 phosphate, sodium laureth-2 phosphate, sodium laureth-3phosphate, sodium laureth-4 phosphate, potassium laureth-1 phosphate,sodium laureth-9 phosphate, sodium myreth-2 phosphate, sodium pareth-1phosphate and mixtures thereof.
 9. The method of claim 8, wherein thesecond composition comprises 0.05% to 5% by weight of sodium laureth-1phosphate.
 10. The method of claim 2, wherein the second compositionfurther comprises a water-soluble fluoride source.
 11. The method ofclaim 10, wherein the water-soluble fluoride source is selected from thegroup consisting of sodium fluoride, stannous fluoride, sodiummonofluorophosphate, amine fluoride, and mixtures thereof; wherein thefirst composition comprises 0.1% to 20% by weight of hydroxyapatite; andwherein the second composition comprises 0.01% to 10% by weight ofsodium laureth-1 phosphate.
 12. The method of claim 2, wherein the firstcomposition is a toothpaste composition, and the second composition is amouth rinse.
 13. The method of claim 2, wherein the first compositionand the second composition are each a mouth rinse.
 14. The method ofclaim 2, wherein the second composition is a mouth rinse, with aviscosity from 100 cps to 5000 cps.
 15. The method of claim 2, whereinthe first composition has a pH from 7 to
 10. 16. The method of claim 2,wherein the second composition has a pH from 6 to
 8. 17. The method ofclaim 2, wherein the contacting steps (a) and (b) each independently hasa contacting duration from 5 seconds to 5 minutes; and the contactingstep (b) is initiated immediately after the conclusion of the contactingstep (a).
 18. The method of claim 17, wherein the first composition is amouth rinse comprising 1% to 5% by weight of hydroxyapatite, and thesecond composition is a mouth rinse comprising 0.05% to 5% by weight ofsodium laureth-1 phosphate and 0.01% to 1% by weight of a sodiumfluoride; and wherein the second composition has a pH from 6.5 to 7.5and a viscosity from 1000 cps to 3000 cps.
 19. An oral care kit,comprising: (a) a first product containing a first composition, whereinthe first composition comprises 0.01% to 99% by weight of awater-insoluble calcium phosphate having a calcium to phosphorus molarratio from 1:1 to 10:1; (b) a second product containing a secondcomposition, wherein the second product is a mouth rinse with a pH from6 to 8 and a viscosity from 100 cps to 5000 cps, and wherein the secondcomposition comprises 0.01% to 99% by weight of an organophosphatehaving the formula:

wherein R is a hydrocarbyl comprising 4 to 22 carbon atoms; X and Y areeach independently an alkylene comprising 2 to 4 carbon atoms; a and bare each independently an integer selected from 0 to 20, and a+b is inthe range from 0 to 20; Z¹ and Z² are each independently selected fromhydrogen, hydrocarbyl comprising 1 to 26 carbons, and a counter ion,provided that at least one of Z¹ and Z² is hydrogen or a counter ion;and (c) instructions instructing a user to first use the first productto contact a tooth surface and thereafter immediately use the secondproduct to contact the tooth surface.
 20. An oral care productcomprising a first container and a second container, wherein the firstcontainer contains a first composition comprising 0.01% to 99% by weightof a water-insoluble calcium phosphate which has a calcium to phosphorusmolar ratio from 1:1 to 10:1, and the second container contains a secondcomposition comprising 0.01% to 99% by weight of an organophosphatehaving the formula:

wherein R is a hydrocarbyl comprising 4 to 22 carbon atoms; X and Y areeach independently an alkylene comprising 2 to 4 carbon atoms; a and bare each independently an integer from 0 to 20, and a+b is in the rangefrom 0 to 20; Z¹ and Z² are each independently selected from hydrogen,hydrocarbyl comprising 1 to 26 carbons, and a counter ion, provided thatat least one of Z¹ and Z² is hydrogen or a counter ion.